C++之运算符重载案例

• 不是所有的操作符都能重载，下面操作符不能重载

::.?:sizeoftypeid

• 实现一个3*3的矩阵类，支持如下操作符：
  • 运算类双目操作符：+ - *
  • 赋值类双目操作符：+= -= *=
  • 单目操作符：-(相反数)
  • 输出操作符：<<

#include<iostream>usingnamespacestd;classMat33{private:intm_a[3][3];public:Mat33(void){for(inti=0;i<3;i++){for(intj=0;j<3;j++){m_a[i][j]=0;}}}Mat33(inta[][3]){for(inti=0;i<3;i++){for(intj=0;j<3;j++){m_a[i][j]=a[i][j];}}}// + a+bconstMat33operator+(constMat33&m)const{inta[3][3]={0};for(inti=0;i<3;i++){for(intj=0;j<3;j++){a[i][j]=m_a[i][j]+m.m_a[i][j];}}Mat33result(a);returnresult;}// - a-bconstMat33operator-(constMat33&m)const{inta[3][3]={0};for(inti=0;i<3;i++){for(intj=0;j<3;j++){a[i][j]=m_a[i][j]-m.m_a[i][j];}}Mat33result(a);returnresult;}// * a*bconstMat33operator*(constMat33&m)const{inta[3][3]={0};for(inti=0;i<3;i++){for(intj=0;j<3;j++){for(intk=0;k<3;k++){a[i][j]+=m_a[i][k]*m.m_a[k][j];}}}Mat33result(a);returnresult;}// += a += b;Mat33&operator+=(constMat33&m){*this=*this+m;// operator+return*this;}// -= a -= b;Mat33&operator-=(constMat33&m){*this=*this-m;// operator-(m)return*this;}// *= a *= b;Mat33&operator*=(constMat33&m){*this=*this*m;// operator*return*this;}//-(取负) -a;constMat33operator-(void)const{Mat33 m;returnm-*this;// operator-(m)}/* * os << a; * */friendostream&operator<<(ostream&os,constMat33&m){for(inti=0;i<3;i++){for(intj=0;j<3;j++){os<<m.m_a[i][j]<<" ";}cout<<endl;}returnos;}};intmain(void){inta1[3][3]={1,2,3,4,5,6,7,8,9};inta2[3][3]={9,8,7,6,5,4,3,2,1};Mat33m1(a1);Mat33m2(a2);cout<<m1<<endl;cout<<m2<<endl;cout<<"m1+m2: "<<endl;cout<<m1+m2<<endl;cout<<"m1-m2: "<<endl;cout<<m1-m2<<endl;cout<<"m1*m2: "<<endl;cout<<m1*m2<<endl;cout<<"m1 += m2: "<<endl;cout<<(m1+=m2)<<endl;cout<<"m1 -= m2: "<<endl;cout<<(m1-=m2)<<endl;cout<<"m1 *= m2: "<<endl;cout<<(m1*=m2)<<endl;cout<<"-m2"<<endl;cout<<-m2<<endl;return0;}